Motor-operated compressor

ABSTRACT

A motor-operated compressor is provided and includes an orbiting scroll and a rear housing supporting a rear surface of the orbiting scroll. The rear housing includes a discharge space communicating with a discharge port of the orbiting scroll formed at a central portion of a surface facing the orbiting scroll, an oil separation space formed at one side of the discharge space to communicate with the discharge space, and an oil storage space formed at an edge portion of the surface facing the orbiting scroll. An oil return passage is provided between the oil separation space and the oil storage space, so as to guide oil separated in the oil separation space to the oil storage space. Accordingly, a space for storing oil separated from a discharged refrigerant is sufficiently secured while allowing the rear housing defining the oil storage space to be easily fabricated.

CROSS-REFERENCE TO RELATED APPLICATION

Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and the right of priority to Korean Patent Application No. 10-2019-0032498, filed on Mar. 21, 2019, the contents of which are incorporated by reference herein in their entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a compressor, and more particularly, a motor-operated compressor employing a scroll compression method and driven by a motor.

2. Description of the Related Art

Compressors are classified into a mechanical type driven by an engine and a motor-operated type driven by a motor. A motor-operated compressor typically employs a scroll compression method suitable for a high compression ratio operation among various compression methods.

In the scroll type motor-operated compressor (hereinafter, referred to as “motor-operated compressor”), a motor unit configured as a drive motor is installed in a hermetic casing, and a compression unit configured by a fixed scroll and an orbiting scroll is disposed at one side of the motor unit. The motor unit and the compression unit are connected to each other by a rotating shaft so that a rotational force of the motor unit is transferred to the compression unit. The rotational force transmitted to the compression unit allows a fluid, such a refrigerant, to be compressed.

The motor-operated compressor can be installed in an electric vehicle to create a refrigeration cycle. Electric cars have a lower power output than engine-powered vehicles, and thus, it is important to reduce weight of automotive components as possible. Accordingly, a small and lightweight motor-operated compressor is more advantageous in terms of reducing an installation space and weight reduction.

However, in the related art motor-operated compressor, as a fixed scroll and an orbiting scroll constituting a compression unit is supported by a frame, there is a limitation in reducing a size and weight of the compressor. Korean Patent Laid-Open Publication No. 10-2014-0136796 (hereinafter, “Patent Document 1”), which is hereby incorporated by reference, discloses a compressor in which a frame that supports a fixed scroll and an orbiting scroll is excluded or removed by using the fixed scroll to serve as the frame. However, the compressor disclosed in Patent Document 1 is mainly developed for an air conditioning system, and a vertical-type type compressor in which a motor unit and a compression unit are arranged in a vertical direction. A compressor used in vehicles is, generally, a horizontal-type compressor in which a motor unit and a compression unit are arranged in a horizontal direction. Accordingly, the compressor of Patent Document 1 is not suitable for the vehicles. Thus, there is a need to develop a horizontal and frame scroll type motor-operated compressor applicable to the vehicles.

SUMMARY

Embodiments disclosed herein provide a motor-operated compressor, capable of reducing the number of components and manufacturing costs by employing a horizontal type compressor equipped with a frame scroll, thereby achieving the small and lightweight motor-operated compressor.

Embodiments disclosed herein further provide a motor-operated compressor, capable of reducing friction loss and abrasion by ensuring a sufficient oil storage space for oil separated from a refrigerant discharged from a compression chamber while employing a horizontal type compressor equipped with a frame scroll.

Embodiments disclosed herein also provide a motor-operated compressor, capable of securing a sufficient oil storage space while facilitating processing (or fabrication) of a rear housing defining the storage space.

Embodiments disclosed herein provide a motor-operated compressor that may include a frame scroll disposed to face a drive motor, an orbiting scroll engaged with the frame scroll to form a compression space, and a housing deposed at an opposite side of the frame scroll to support the orbiting scroll. The housing may be provided with a discharge space, an oil storage space having an annular shape formed along a circumference of the discharge space, and an oil separation space formed between the discharge space and the oil storage space.

Embodiments disclosed herein may further provide a motor-operated compressor that may include a frame scroll, an orbiting scroll, and a rear housing sequentially based on a drive motor. A recessed oil storage space may be provided at one side surface of the rear housing that faces the orbiting scroll. The rotating scroll may be provided with an oil passage communicating with the oil storage space.

Embodiments disclosed herein may further provide a motor-operated compressor that may include a thrust plate provided between an orbiting scroll and a housing that supports the orbiting scroll in a direction to a frame scroll. A hermetically sealed space may be provided at both side surfaces of the thrust plate, respectively. The hermetically sealed space may be separated from an inner space and a discharge space of the housing. A pressure reducing member may be provided between the hermetically sealed space and the discharge space.

Embodiments disclosed herein may further provide a motor-operated compressor that may include a main housing having a suction space, a motor unit disposed at the suction space of the main housing, a rotating shaft coupled to the motor unit, a fixed scroll coupled to the main housing to support the rotating shaft, and provided with an inlet port communicating with the suction space, an orbiting scroll coupled to the rotating shaft to perform an orbiting motion with respect to the fixed scroll, forming a compression space, and provided with a discharge port, and a rear housing coupled to the main housing.

The rear housing may be provided with a discharge space communicating with the discharge port of the orbiting scroll formed at a central portion of a surface facing the orbiting scroll, an oil storage space formed at an edge portion of the surface facing the orbiting scroll, and an oil return passage that guides oil separated in the discharge space to the oil storage space.

The oil storage space may be formed such that a surface facing the orbiting scroll is opened.

A first annular-shaped support surface may be provided at an inner circumferential side of the oil storage space, and the first annular-shaped support surface may be provided with a first sealing member that seals between the oil storage space and the discharge space.

In addition, a second annular-shaped support surface may be provided at an outer circumferential side of the oil storage space, and the second annular-shaped support surface may be provided with a second sealing member that seals between the oil storage space and the suction space.

At least one oil storage space partitioning protrusion that connects between the first annular-shaped support surface and the second annular-shaped support surface may be provided therebetween. The oil storage space partitioning protrusion may have an axial height lower than an axial height of the first annular-shaped support surface and the second annular-shaped support surface.

Further, at least one oil storage space partitioning protrusion that connects between the first annular-shaped support surface and the second annular-shaped support surface may be provided therebetween. The oil storage space partitioning protrusion may be provided with a space communication groove.

Furthermore, at least one oil storage space partitioning protrusion that connects between the first annular-shaped support surface and the second annular-shaped support surface may be provided therebetween. The oil storage space partitioning protrusion may be provided with an anti-rotation pin rotatably inserted into an anti-rotation ring provided at the orbiting scroll, so as to prevent rotation of the orbiting scroll.

In addition, the oil storage space may be formed in an annular shape, and be provided with a plurality of pin fixing protrusions formed along a circumferential direction with a predetermined distance therebetween. Each of the plurality of pin fixing protrusions may be provided with an anti-rotation pin rotatably inserted into an anti-rotation ring provided at the orbiting scroll.

Here, an outlet end of the oil return passage may communicate with the oil storage space at a position lower than a position of the discharge space.

In addition, the outlet end of the oil return passage may be provided on a side wall surface of the oil storage space to form a return passage forming protrusion axially protruding to a predetermined height. The return passage forming protrusion may be provided with a flow controller configured to control a flow rate of oil passing through the oil return passage.

The orbiting scroll may be provided with an oil guide passage, and one end of the oil guide passage may communicate with the oil storage space of the rear housing.

In addition, a central portion of the orbiting scroll may be provided with a rotating shaft coupling portion to which the rotating shaft is coupled. Another end of the oil guide passage may communicate with the rotating shaft coupling portion.

An oil supply passage may be provided at an end portion of the rotating shaft inserted into the rotating shaft coupling portion, so as to communicate with the oil guide passage. The oil supply passage may include an oil supply groove formed at the end portion of the rotating shaft in an axial direction, and a plurality of oil supply holes penetrating toward the rotating shaft coupling portion and the fixed scroll from the oil supply groove.

The oil guide passage may be located higher than the oil return passage.

The orbiting scroll may be further provided with a low-pressure side oil supply passage communicating with the oil guide passage. The low-pressure side oil supply passage may include a low-pressure side oil supply hole axially penetrating through an orbiting wrap provided at the orbiting scroll.

An oil supply communication groove may be further provided at an end portion of the orbiting wrap facing the fixed scroll. The oil supply communication groove may be formed to be connected to a side wall surface of the orbiting wrap from an end portion of the low-pressure side oil supply hole.

Here, a thrust plate may be provided between the orbiting scroll and the rear housing. A plurality of scroll-side sealing members may be provided between the thrust plate and the orbiting scroll to be spaced apart by predetermined intervals in a radial direction. A plurality of housing-side sealing members may be provided between the thrust plate and the rear housing in the radial direction with the oil storage space interposed therebetween.

The thrust plate may be provided with a plurality of pin holes formed along a circumferential direction so that an anti-rotation pin that prevents rotation of the orbiting scroll is penetratingly coupled. At least one communication hole may be formed to provide communication between the plurality of scroll-side sealing members and the plurality of housing-side sealing members.

Embodiments disclosed herein may further provide a motor-operated compressor that may include a first housing having a suction space, a motor unit provided at one end of the first housing, a rotating shaft coupled to the motor unit to be rotatable, a first scroll disposed at the suction space of the first housing and provided at another end of the first housing to face the motor unit, coupled to the first housing to support the rotating shaft, and provided with an inlet port communicating with the suction space, a second scroll coupled to the rotating shaft to perform an orbiting motion with respect to the first scroll, forming a compression space at a first side surface thereof facing the first scroll, and provided with a discharge port, and a second housing disposed to face a second side surface opposite to the first side surface of the second scroll so as to be coupled to the first housing.

The second housing may be provided with a discharge space communicating with the discharge port of the second scroll formed at a central portion of a surface facing the second scroll, an oil separation space formed at one side of the discharge space to communicate with the discharge space, and an oil storage space formed at an edge portion of the surface facing the second scroll to communicate with the oil separation space.

The second scroll may be provided with an oil guide passage communicating with the oil storage space of the second housing. The rotating shaft may be provided with an oil supply passage communicating with the oil guide passage, so as to guide oil in the oil storage space to a bearing surface that supports the rotating shaft.

In a motor-operated compressor according embodiments, a horizontal type compressor equipped with a frame scroll may be employed to reduce the number of components and manufacturing costs, thereby achieving the small and lightweight motor-operated compressor.

In addition, in the motor-operated compressor according embodiments, a discharge space for accommodating a refrigerant discharged from a compression chamber, and an oil storage space formed at the adjacent to the discharge space to store oil separated from the refrigerant discharged from the compression chamber are provided, thereby sufficiently securing the oil storage space. This allows oil in the oil storage space to be quickly supplied to a portion or part requiring lubrication. As a result, friction loss or abrasion caused by an insufficient amount of oil can be reduced.

Further, in the motor-operated compressor according embodiments, the oil storage space may be formed to be opened to one side surface of a rear housing, allowing the rear housing to be easily fabricated (or processed) and manufacturing costs of the rear housing to be reduced.

In addition, in the motor-operated compressor according embodiments, as an outlet end of an oil return passage that provides communication between an oil separation space and the oil storage space is formed through a side wall surface of the oil storage space at a position lower than the discharge space, oil separated from the oil separation space can be quickly introduced into the oil storage space.

Furthermore, in the motor-operated compressor according embodiments, a plurality of scroll-side sealing members may be provided between a thrust plate and an orbiting scroll to be spaced apart by predetermined intervals in a radial direction, and a plurality of housing-side sealing members may be provided in the radial direction with the oil storage space interposed therebetween. Accordingly, the oil storage space may be sealed with respect to each of a discharge pressure space and a suction pressure space, and thus the oil storage space can maintain an intermediate pressure. As a result, oil supplied can be maintained at an intermediate pressure, thereby preventing performance of the compressor from being degraded or lowered.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an outer appearance of a motor-operated compressor according to an embodiment;

FIG. 2 is an exploded perspective view of the motor-operated compressor of FIG. 1;

FIG. 3 is an assembled cross-sectional view illustrating an inside of the motor-operated compressor of FIG. 1;

FIG. 4 is a cross-sectional view illustrating a coupled state of a fixed scroll and an orbiting scroll in a compression unit according to an embodiment;

FIG. 5 is an enlarged cross-sectional view illustrating a portion with respect to a rotating shaft in FIG. 3;

FIG. 6 is a perspective view of the orbiting scroll according to an embodiment, viewed from the rear;

FIG. 7 is a cross-sectional view taken along line “V-V” of FIG. 6;

FIG. 8 is a perspective view of a rear housing according to an embodiment, viewed from the front;

FIG. 9 is a planar view of the rear housing of FIG. 8, viewed from the front;

FIG. 10 is a cross-sectional view taken along line “VI-VI” of FIG. 9;

FIG. 11 is a planar view of an oil storage space according to another embodiment;

FIG. 12 is a cross-sectional view of an oil guide passage according to another embodiment;

FIG. 13 is an enlarged cross-sectional view illustrating a portion of the motor-operated compressor according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Description will now be given in detail of a motor-operated compressor according to exemplary embodiments disclosed herein, with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating an outer appearance of a motor-operated compressor according to an embodiment.

Referring to FIG. 1, a motor-operated compressor 100 according to this embodiment may include a compression module 101 and an inverter module 102. The compression module 101 refers to a set of parts (or components) for compressing a fluid such as a refrigerant, and the inverter module 102 refers to a set of parts for controlling driving of the compression module 101. The inverter module 102 may be coupled to a front side of the compression module 101. Hereinafter, a side where the inverter module 102 is installed is referred to as a “front side”, and a side where the compression module 101 is installed is referred to as a “rear side”, respectively. As a fluid (hereinafter, “refrigerant”) to be compressed or pressurized is introduced into an inlet port 111 and is then discharged to an exhaust port 126, the inverter module 102 disposed close to the inlet port 111 should be coupled to the front side of the compression module 101, which is more suitable for cooling the inverter module 101.

The outer appearance of the compression module 101 may be defined by a main housing 110, which is a first housing, and a rear housing 120, which is a second housing. For example, the main housing 110 may have a closed front end and an opened rear end, and the rear housing 120 may have an opened front end and a closed rear end. Accordingly, the rear end of the main housing 110 and the front end of the rear housing 120 may communicate with each other to form a sealed casing for the compression module 101.

FIG. 2 is an exploded perspective view of the motor-operated compressor of FIG. 1, and FIG. 3 is an assembled cross-sectional view illustrating an inside of the motor-operated compressor of FIG. 1.

Referring to these drawings, the main housing 110 may have a hollow cylindrical shape, a hollow polygonal cylinder shape, or the like. The main housing 110 may be disposed to extend toward a horizontal direction. The main housing 110 may surround or cover a motor unit 130 to be described hereinafter. One axial end of the main housing 110 may be closed, and another axial end of the main housing 110 may be open.

The inlet port 111 may be formed on an outer circumferential surface of the main housing 110. The inlet port 111 may provide a flow path that supplies a refrigerant (e.g., R134a, R32, CO2, etc.) to an inner space of the compression module 101.

A first scroll support surface 112 that axially supports a support protrusion 143 of a fixed scroll 140 to be described hereinafter may be provided on an inner circumferential surface of the rear end of the main housing 110. The first scroll support surface 112 may be formed in a stepped manner to have an arc shape, or may be formed in a stepped manner to have an annular shape. The first scroll support surface 112 may be provided with a plurality of coupling grooves 112 a formed along a circumferential direction with a predetermined distance therebetween so as to correspond to a bolt passing groove 143 c of the fixed scroll 140 and a coupling hole 120 b of the rear housing 120, which will be described hereinafter.

The rear housing 120 may be coupled to the rear end of the main housing 110. The rear housing 120 may cover the rear end of the main housing 110. The exhaust port 126 may be provided at the rear housing 120, and an oil separator 123 a may be installed at the exhaust port 126.

In addition, the rear housing 120 may be disposed to face a rear surface of an orbiting scroll 150 to be described hereinafter, so as to form a compression unit accommodating space 121, a discharge space 122, an oil separation space 123, and an oil storage space 124, which are important features of the present disclosure, so this will be described in detail later together with relevant members.

Referring back to FIGS. 2 and 3, as for the compression module 101, the motor unit 130 (drive unit or drive motor) and a compression unit 105 may be axially disposed in an inner space of the main housing 110 defining a portion or part of the casing, and the motor unit 130 and the compression unit 105 may be connected by a rotating shaft 160. The motor unit 130 may be located at a front side of the main housing 110, and the compression unit 105 may be located at a rear side of the main housing 110.

Here, as the inlet port 111 is provided at the main housing 110, the inner space of the main housing 110 may form a suction space S1, and thus, the motor unit 130 and the compression unit 105 are located at the suction space S1 forming a suction pressure. Therefore, the suction space S1 may also be referred to as a motor chamber.

The motor unit 130 may be configured to generate a driving force required for the orbiting scroll 150 of the compression unit 105 to perform an orbiting motion. The motor unit 130 may also be referred to as a drive motor, and configured as an electric motor.

The motor unit 130, or the drive motor may include a stator 131 and a rotor 132. The stator 131 may be fixedly inserted into an inner circumferential surface of the main housing 110 in a shrink-fitting manner (or hot press fitting). Alternatively, the stator 131 may be fixed by welding after insertion or may be fixed by using another fixing member.

The rotor 132 may be disposed inside the stator 131 in a rotatable manner. When an electric power is applied to the stator 131, the rotor 132 is rotated by electromagnetic interaction with the stator 131.

The rotating shaft 160 may be coupled to a center of the rotor 132. An eccentric portion 164 may be provided at the rotating shaft 160 to be eccentrically coupled to the orbiting scroll 150. This allows a rotational force of the drive motor to be transferred to the orbiting scroll 150 by the rotating shaft 60. This will be described again later since the rotating shaft 160 is related to the present disclosure.

FIG. 4 is a cross-sectional view illustrating a coupled state of a fixed scroll and an orbiting scroll in a compression unit according to an embodiment, and FIG. 5 is an enlarged cross-sectional view illustrating a portion with respect to a rotating shaft in FIG. 3.

Referring to FIG. 4, the compression unit 105 is configured to compress a refrigerant. The compression unit 105 may include the fixed scroll 140 defining the frame scroll (a frame scroll and the fixed scroll are the same member, so hereinafter the terms frame scroll and fixed scroll may be used interchangeably) and the orbiting scroll 150. The compression unit 105 may be defined by the fixed scroll 140 and the orbiting scroll 150. The fixed scroll 140 and the orbiting scroll 150 may also be referred to as a first scroll and a second scroll, respectively.

The fixed scroll 140 and the orbiting scroll 150 may be coupled to each other to form a pair of compression chambers. As the orbiting scroll 150 performs an orbiting motion, a volume of the compression chambers is repeatedly changed, and a refrigerant is compressed in the compression chambers, accordingly.

The fixed scroll and the orbiting scroll will be described in detail with reference to FIG. 3.

The fixed scroll 140 may be located relatively close to the motor unit 130, and the orbiting scroll 150 may be located relatively far from the motor unit 130. The fixed scroll 140 may be disposed between the orbiting scroll 150 and the main housing 110 in an axial direction. The orbiting scroll 150 may be disposed between the fixed scroll 140 and the rear housing 120 in the axial direction.

The fixed scroll 140 may include a fixed end plate 141 and a fixed wrap 142. The fixed end plate 141 may have a substantially disk shape. A plurality of support protrusions 143 may be formed on an outer circumferential surface of the fixed end plate 141 along a circumferential direction with a predetermined distance therebetween. The bolt passing groove 143 c through which a coupling bolt described hereinafter passes may be provided between the support protrusions 143. Accordingly, an edge of a first side surface 143 a of the support protrusion 143 facing the drive motor may be axially supported with respect to the front side by the first scroll support surface 112 provided on the inner circumferential surface of the main housing 110. A coupling bolt B passing through the coupling hole 120 b of the rear housing 120 and the bolt passing groove 143 c of the fixed scroll 140 may be fastened to the coupling groove 112 a, so that the main housing 110 of the fixed scroll 140 and the rear housing 120 are coupled to each other.

Of both side surfaces of the support protrusion 143, a second side surface 143 b facing the orbiting scroll 150 may be in close contact with an open end surface 120 a of the rear housing 120. Accordingly, the first side surface 143 a of the support protrusion 143 of the fixed scroll 140 may be in close contact with the first scroll support surface 112 of the main housing 110 to be axially supported, and the second side surface 143 b of the support protrusion 143 of the fixed scroll 140 may be in close contact with the opened end surface 120 a of the rear housing 120 to be axially supported.

In addition, a suction port 145 may be formed through the support protrusion 143 so that the suction space S1 and a suction chamber V1 communicate with each other. Accordingly, a height (i.e. radial extent) of the first scroll support surface 112 may be preferably formed to an extent that does not cover the suction port 145.

Meanwhile, a scroll bearing portion 146 axially extending toward the drive motor may be provided at a central portion of the fixed end plate 141, and a rotating shaft accommodating portion 147 may be formed through the scroll bearing portion 146 in the axial direction.

A main bearing 171 (see FIG. 5) may be fixedly inserted into an inner circumferential surface of the rotating shaft bearing portion 147, so that a main bearing portion 162 of the rotating shaft 160 is inserted and radially supported. The main bearing 171 may be configured as a ball bearing. In this embodiment, however, a bush bearing is employed to reduce manufacturing costs.

A sealing member (not shown) may be provided at a front end of the rotating shaft accommodating portion 147, so as to provide a seal between the rotating shaft 160 and the fixed scroll 140. Accordingly, as for the rotating shaft 160, the main bearing portion 162 provided at a rear side with respect to the rotor 132 of the drive motor (motor unit 130) may be radially supported by the fixed scroll 140.

A sub bearing portion 163 formed at a front side of the rotating shaft 160 may be supported by a sub bearing 172 provided at a front side surface of the main housing 110. The sub bearing 172, configured as a ball bearing, may be inserted into a shaft support portion 113 provided on a front inner surface of the main housing 110. As the sub bearing 172 is implemented as the ball bearing, the rotating shaft 160 may be radially and axially supported by the sub bearing 172.

Referring to FIGS. 3 and 4, the fixed wrap 142 may protrude toward the orbiting scroll 150 from a second side surface 141 b of the fixed end plate 141 facing the orbiting scroll 150. The fixed wrap 142 may have an involute shape. In this embodiment, however, the fixed wrap 142 may have a non-volute shape as the rotating shaft 160 penetrates through the fixed scroll 140 and is inserted into and coupled to the orbiting scroll 150. The shape of the fixed wrap will be discussed later together with an orbiting wrap.

FIG. 6 is a perspective view of the orbiting scroll according to an embodiment, viewed from the rear, and FIG. 7 is a cross-sectional view taken along line “V-V” of FIG. 6.

Referring back to FIG. 3, the orbiting scroll 150 may be disposed to face the fixed scroll 140. The orbiting scroll 150 may be coupled to the eccentric portion 164 (see FIG. 5) provided at a rear end of the rotating shaft 160. Accordingly, the orbiting scroll 150 may be eccentrically coupled to the rotating shaft 160. The orbiting scroll 150 may receive a rotational force from the eccentric portion 164 and may perform an orbiting motion by an anti-rotation mechanism 190.

Referring to FIGS. 3 to 7, the orbiting scroll 150 may include an orbiting end plate 151, an orbiting wrap 152, and a rotating shaft coupling portion 153.

The orbiting end plate 151 may have a disk shape corresponding to the fixed end plate 141. If the fixed end plate 141 has a cross section that correspond to a disk (disc), then the orbiting end plate 151 has a disk-shaped cross section.

Of both axial side surfaces of the orbiting end plate 151, when a surface facing the fixed scroll 140 is a first side surface 151 a and a surface facing the rear housing 120 is a second side surface 151 b, the orbiting wrap 152 may be provided on the first side surface 151 a, and an anti-rotation groove 154 may be formed on the second side surface 151 b.

The orbiting wrap 152 may protrude from the first side surface 151 a of the orbiting end plate 151 toward the fixed scroll 140 into an involute curve shape, an Archimedean spiral shape, or a logarithmic spiral shape.

However, in this embodiment, the orbiting wrap 152 together with the fixed wrap 142 may be formed in a non-involute shape. This is to reduce a pressure difference between compression pockets formed at an outer side with respect to the fixed wrap 142 and formed at an inner side with respect to the fixed wrap 142, as the rotating shaft 160 penetrates through the fixed scroll 140 to be coupled to the orbiting wrap 152 of the orbiting scroll 150 in a radially overlapping manner. For example, as illustrated in FIG. 4, the orbiting wrap 152 according to this embodiment may be provided with a protruding portion 153 a formed at an end portion of a discharge side constituting the rotating shaft coupling portion 153, so as to extend a crank angle (compression angle) of the inner side compression pocket. This allows a compression period (or cycle) to be extended. Further, the pressure difference between the opposite compression pockets may be minimized by increasing a compression ratio of the inner side compression pocket.

The rotating shaft coupling portion 153 may be provided at a central portion of the orbiting end plate 151. The rotating shaft coupling portion 153 may protrude toward the fixed scroll 140 from the first side surface 151 a of the orbiting end plate 151. The rotating shaft coupling portion 153 may be provided at a position corresponding to an involute base circle defining the orbiting wrap 152. Accordingly, the rotating shaft coupling portion 153 may form the innermost part or portion of the orbiting wrap 152.

The rotating shaft coupling portion 153 may have a hollow cylindrical shape so as to accommodate the eccentric portion 164 of the rotating shaft 160 therein. The rotating shaft coupling portion 153 may be formed to cover or surround the eccentric portion 164 of the rotating shaft 160.

The rotating shaft coupling portion 153 of the orbiting scroll 150 may have one open side. For example, the rotating shaft coupling portion 153 of the orbiting scroll 150 may be open toward the fixed scroll 140, but a rear surface thereof opposite to the open side may be blocked by the orbiting end plate 151. Accordingly, the eccentric portion 164 of the rotating shaft 160 may be inserted into the rotating shaft coupling portion 153 of the orbiting scroll 150, but may not penetrate through the orbiting end plate 151.

Referring to FIGS. 6 and 7, a plurality of anti-rotation grooves 154, a plurality of sealing grooves 155 a and 155 b, and a discharge guide groove 156 are provided on the second side surface 151 b of the orbiting end plate 151.

The plurality of anti-rotation grooves (precisely, anti-rotation rings) 154 and an anti-rotation pin 192 (see FIG. 11) to be described hereinafter defining the anti-rotation mechanism 190 may be provided to suppress a rotary motion of the orbiting scroll 150. The plurality of anti-rotation grooves 154 may be disposed to be spaced apart by predetermined intervals along a circumferential direction. The plurality of anti-rotation grooves 154 may be formed to correspond to a plurality of anti-rotation pins 192. An anti-rotation ring 191 may be inserted and coupled to each of the plurality of anti-rotation grooves 154, respectively. Accordingly, the anti-rotation pin 192 may be rotatably inserted into the anti-rotation ring 191.

Sealing members 181, 182 may be inserted into the plurality of sealing grooves 155 a and 155 b, respectively, so as to provide a seal between the orbiting scroll 150 and a thrust plate 180 to be described hereinafter. This is to form a rear-side intermediate pressure space S22 so that the oil storage space 124 described hereinafter maintains an intermediate pressure. The plurality of sealing grooves 155 a and 155 b may be disposed radially inward and outward, respectively, with the plurality of anti-rotation grooves 154 interposed therebetween. The sealing groove disposed radially inward may be referred to as a scroll-side first sealing groove 155 a and the sealing groove disposed radially outward may be referred to as a scroll-side second sealing groove 155 b.

For example, the scroll-side first sealing groove 155 a may be provided adjacent to a central portion of the second side surface 151 b of the orbiting end plate 151, and the scroll-side second sealing groove 155 b may be provided adjacent to an edge portion of the second side surface 151 b of the orbiting end plate 151. A scroll-side first sealing member 181 inserted into the scroll-side first sealing groove 155 a may have a smaller diameter than a scroll-side second sealing member 182 inserted into the scroll-side second sealing groove 155 b. Accordingly, the rear-side intermediate pressure space S22 may be separated from the discharge space 122 by the scroll-side first sealing member 181, and may be separated from the suction space S1 by the scroll-side second sealing member 182.

In addition, the scroll-side first sealing groove 155 a and the scroll-side second sealing groove 155 b may be eccentrically disposed with respect to each other. In more detail, the scroll-side second sealing groove 155 b may be substantially coaxial with an axial center Oc (see FIG. 11) of the rotating shaft 160, but the scroll-side first sealing groove 155 a may be eccentrically formed from the axial center Od (see FIG. 11) of the rotating shaft 160. This is because as the motor-operated compressor according to this embodiment has a shaft through structure, a discharge port 157 to be described hereinafter may be eccentrically disposed from the axial center.

The discharge guide groove 156 may be engraved or depressed from the second side surface 151 b of the orbiting end plate 151 by a predetermined depth. Discharge guide groove 156 may be formed at a central portion of the second side surface 151 b of the orbiting plate 151. As described above, as the discharge port 157 is eccentrically disposed from the axial center Oc, the discharge guide groove 156 may also be eccentrically disposed from the axial center Oc. The scroll-side first sealing groove 155 a (see FIG. 6) may be provided on an inner circumferential surface of the discharge guide groove 156 in a stepped manner.

In addition, the discharge port 157 may be provided in the discharge guide groove 156. The discharge port 157 may penetrate between the first side surface 151 a and the second side surface 151 b of the orbiting end plate 151. An end portion of the discharge port 157 may be provided with a check valve 158 to open and close the discharge port 157, which acts a kind of a discharge valve.

The orbiting end plate 151 may be provided with an oil guide passage 159 that guides oil introduced into the oil storage space 124 of the rear housing 120 to an oil supply passage 165 of the rotating shaft 160. This is a feature of the present disclosure, so this will be discussed later together with the rear housing.

Referring back to FIGS. 2 and 3, the rotating shaft 160 may be connected to the motor unit 130 and the orbiting scroll 150, respectively, so that a driving force generated in the motor unit 130 is transferred to the orbiting scroll 150. To this end, the rotating shaft 160 may extend from the front to the rear of the motor-operated compressor 100. A direction to which the rotating shaft 160 extends may be an axial direction of the rotating shaft 160. The rotating shaft 160 may be fixed to the rotor 132 in a shrink-fitting manner (or hot press fitting).

Referring to FIG. 5, the rotating shaft 160 may include a motor coupling portion 161, the main bearing portion 162, the sub bearing portion 163, and the eccentric portion 164.

The motor coupling portion 161 may be coupled through the center of the rotor 132.

The main bearing portion 162 corresponds to a rear side of the motor coupling portion 161, and the sub bearing portion 163 corresponds to a front side of the motor coupling portion 161. Accordingly, the main bearing portion 162 and the sub bearing portion 163 may axially extend from the motor coupling portion 161 to directions opposite from each other. Each of the main bearing portion 162 and the sub bearing portion 163 may have an outer diameter different from a diameter of the motor coupling portion 161. A center of the main bearing portion 162 and a center of the sub bearing portion 163 may coincide with a center of the motor coupling portion 161, respectively.

The main bearing portion 162 may be inserted to axially penetrate through the rotating shaft accommodating portion 147 of the fixed scroll 140 to be described hereinafter. The main bearing 171 implemented as a bush bearing may be coupled to the rotating shaft accommodating portion 147. Accordingly, the main bearing portion 162 may be radially supported by the main bearing 171 in a rotatable manner.

The sub bearing portion 163 may be coupled to the shaft support portion 113 provided on a front surface of the main housing 110. The sub-bearing 172 implemented as a ball bearing may be coupled to the shaft support portion 113. Accordingly, the sub bearing portion 163 may be radially and axially supported by the sub bearing 172 in a rotatable manner.

The eccentric portion 164 is a portion that corresponds to a rear side of the main bearing portion 162. The eccentric portion 164 may axially extend from the main bearing portion 162. The eccentric portion 164 may have an outer diameter smaller than the outer diameter of the main bearing portion 162.

A center of the eccentric portion 164 may be eccentrically disposed with respect to the center of the main bearing portion 162. Referring to FIG. 4, a center Oe of the eccentric portion 164 may be eccentrically disposed from the center of the motor coupling portion 161 in the axial direction of the rotating shaft 160 or from the axial center Oc of the rotating shaft 160 which is coaxial with the center of the motor coupling portion 161. The eccentric portion 164 may be formed at the rear end of the rotating shaft 160 to be inserted into the rotating shaft coupling portion 153 of the orbiting scroll 150.

The oil supply passage 165 may be provided in the rotating shaft 160 so as to guide oil introduced into the rotating shaft coupling portion 154 of the orbiting scroll 150 to the main bearing portion 162 and the eccentric portion 164. The oil supply passage 165 may include an oil supply groove 165 a and a plurality of oil supply holes 165 b and 165 c.

The oil supply groove 165 a may be formed as a groove recessed from the rear end of the rotating shaft 160 to a predetermined depth, and the oil supply holes 165 b, 165 c may be implemented as holes, respectively, each penetrating from the oil supply groove 165 a to an outer circumferential surface of the rotating shaft 160, namely, to an outer circumferential surface of the main bearing portion 162 and an outer circumferential surface of the eccentric portion 164, respectively. The oil supply hole formed through the main bearing portion 162 may be referred to as a first oil supply hole 165 b, and the oil supply hole formed through the eccentric portion 164 may be referred to as a second oil supply hole 165 c.

The first oil supply hole 165 b and the second oil supply hole 165 c may have the same inner diameter and may penetrate in the same direction. In some cases, however, an inner diameter of the second oil supply hole 165 c may be larger than an inner diameter of the first oil supply hole 165 b. This may allow more oil to be supplied to the eccentric portion 164 than the main bearing portion 162, and thus, oil may be supplied to the compression chambers more quickly.

Meanwhile, as described above, the casing according to this embodiment may be configured as the main housing 110 and the rear housing 120. The fixed scroll 140 provided between the main housing 110 and the rear housing 120 may be axially supported to be fixed.

FIG. 8 is a perspective view of a rear housing according to an embodiment, viewed from the front, FIG. 9 is a planar view of the rear housing of FIG. 8, viewed from the front, and FIG. 10 is a cross-sectional view taken along line “VI-VI” of FIG. 9.

Referring to these drawings, the rear housing 120 may be coupled to the rear end of the main housing 110 while axially supporting the fixed scroll 140. Accordingly, the front end of the rear housing 120, namely, an open end surface 120 a of the rear housing 120 may be wider (or larger) than a width of the rear end (opened end surface) of the main housing 110, so as to support both the rear end of the main housing 110 and the support protrusion 143 of the fixed scroll 140.

In addition, the open end of the rear housing 120 may be provided with a plurality of coupling holes 120 b and a bolt accommodating grooves 120 c, respectively, formed along an inner circumferential surface of the rear housing 120, so that the coupling bolt B penetrates therethrough. A gasket or an O-ring may be provided on the open end surface 120 a of the rear housing 120 to be coupled to the main housing 110, thereby enhancing a sealing effect. The coupling hole 120 b and the bolt accommodating groove 120 c may be formed in line with the bolt passing groove 143 c provided between the support protrusions 143 of the fixed scroll 140, and the coupling groove 112 a of the main housing 110.

The inner space of the rear housing 120 may include sequentially the compression unit accommodating space 121, the discharge space 122, the oil separation space 123, and the oil storage space 124 starting from the compression chamber V in a refrigerant flowing direction. An inner diameter of the compression unit accommodating space 121 may be wider (or larger) than an inner diameter of the discharge space 122. Accordingly, a second scroll support surface 125 may be provided between the compression unit accommodating space 121 and the discharge space 122 in a stepped manner, so as to support the rear surface of the orbiting scroll 150. An outer circumference and an inner circumference of the second scroll support surface 125 may extend to the compression unit accommodating space 121 and the discharge space 122, respectively.

The second scroll support surface 125 may be provided with a plurality of sealing grooves 125 a and 125 b spaced apart from each other in a radial direction. For example, a housing-side first sealing groove 125 a may be provided at a central portion of the second scroll support surface 125 so that the housing-side first sealing member 183 (see FIG. 10) that comes into close contact with a central portion of a rear surface of the thrust plate 180 is inserted, and a housing-side second sealing groove 125 b may be provided at an edge portion of the second scroll support surface 125 so that the housing-side second sealing member 184 (see FIG. 10) that comes into close contact with an edge portion of the rear surface of the thrust plate 180 is inserted.

The rear-side intermediate pressure space S22 communicating with a front-side intermediate pressure space S21 provided between the scroll-side first sealing member 181 and the scroll-side second sealing member 182 may be provided between the housing-side first sealing member 183 and the housing-side second sealing member 184. The front-side intermediate pressure space S21 and the rear-side intermediate pressure space S22 may communicate with each other through a pin hole 180 a formed at the thrust plate 180 or an oil communication hole 180 b.

The discharge space 122 may be provided inside the housing-side first sealing member 183. The discharge space 122 may be further recessed toward the rear side than the compression unit accommodating space 121. The discharge space 122 may be disposed to face the discharge guide groove 156 of the orbiting scroll 150 to communicate with the discharge port 157. As shown in FIG. 9, a center Od of the discharge space 122 may be eccentrically disposed with respect to a center of the rear housing 120, namely, the axial center Oc of the rotating shaft 165, like the discharge guide groove 156. The housing-side first sealing member 183 may be eccentrically disposed with respect to the housing-side second sealing member 184. Accordingly, the rear-side intermediate pressure space S22 to be described hereinafter may be disposed eccentrically with respect to the axial center Oc. This is also the case for the front-side intermediate pressure space S21.

Referring to FIGS. 8 and 10, the discharge space 122 may be formed in a cylindrical shape having a closed rear surface on which the oil separation space 123 is provided. Accordingly, the rear surface of the discharge space 122 may slightly protrude forward to secure the oil separation space 123. An oil separation communication hole 122 a may be provided at the rear surface of the discharge space 122 to communicate with the oil separation space 123.

The oil separation space 123 may be formed in a vertical direction or in a direction slightly inclined with respect to the vertical direction. The oil separator 123 a may be installed in the oil separation space 123 to separate oil from a refrigerant introduced into the oil separation space 123. After separation, the refrigerant flows into a refrigeration cycle via the exhaust port 126 formed through an upper end of the oil separation space 123, while the oil in a mist state flows into the oil storage space 124 via an oil return (or recovery) passage 127 formed though a lower end of the oil separation space 123.

The oil storage space 124 may be provided between the housing-side first sealing member 183 and the housing-side second sealing member 184. That is, the oil storage space 124 may be formed on the second scroll support surface 125 to cover or surround an outer circumference of the discharge space 122.

An inner diameter of the storage space 124 may be larger (or greater) than an inner diameter of the second scroll support surface 125. Of the second scroll support surface 125, a first annular-shaped support surface 128 a may be provided between the discharge space 122 and the oil storage space 124, and the housing-side first sealing groove 125 a may be provided on the first annular-shaped support surface 128 a. The first annular-shaped support surface 128 a may be formed in an annular-shaped partition wall so as to separate the discharge space 122 and the oil storage space 124 from each other.

In addition, an outer diameter of the oil storage 124 may be smaller than an outer diameter of the second scroll support surface 125. Accordingly, of the scroll support surface 125, a second annular-shaped support surface 128 b may be formed outside of the oil storage space 124. The housing-side second sealing groove 125 b may be provided on the second annular-shaped support surface 128 b.

As such, as the oil storage space 124 is separately provided but is opened toward the opened end of the rear housing, the rear housing 120 may be easily manufactured while expanding a volume of the storage space 124.

In the oil storage space 124 according to this embodiment, rigidity of the rear housing 120 may be enhanced by a plurality of connecting ribs 128 c (or oil storage space partitioning protrusion). Accordingly, the oil storage space 124 may be divided into a plurality of oil storage chambers 124 a, allowing rigidity of the rear housing 120 to be enhanced while forming the oil storage space 124.

For example, the connecting rib 128 c may radially connect between the first annular-shaped support surface 128 a and the second annular-shaped support surface 128 b. Accordingly, the oil storage space 124 may be divided into the plurality of oil storage chambers 124 a having an arc shape. As a result, as described above, the rear housing 120 may be physically reinforced while distributing a pressure of the storage space 124. Further, as shown in FIG. 9, the connecting rib 128 c may be formed such that the coupling hole 120 b is radially located at a portion where the coupling bolt B is fastened, namely, a width range of the connecting rib 128 c. This may prevent the rear housing 120 from being deformed by a coupling force applied when the rear housing 120 is coupled to the main housing 110.

In some cases, however, the second annular-shaped support surface 128 b may be excluded. An outer end of the connecting rib 128 c may be connected to the inner circumferential surface of the rear housing 120 defining the compression unit accommodation space 121, allowing the oil storage space 124 to be further increased.

The oil storage space 124 according to this embodiment may be divided into the plurality of oil storage chambers 124 a while communicating with each other.

Referring to FIG. 10, a height of the connecting rib 128 c may be lower (or shorter) than a height of the second scroll support surface 125 so that the plurality of storage chambers 124 a communicate with each other. Alternatively, the height of the connecting rib 128 c may be equal to the height of the scroll support surface 125. Here, an oil storage chamber connecting passage 128 d (or space communication groove), such as a connection groove and a connection hole, may be formed at each of the connecting ribs 128 c to allow neighboring oil storage chambers to communicate with each other. Also, a connection groove or a connection hole may be provided in each of the connecting ribs 128 c even when the height of the connecting ribs 128 c is lower than the height of the second scroll support surface 125.

In addition, each of the connection ribs 128 c may be provided with a pin groove 128 e, respectively, to which the anti-rotation pin 192 is fixed. Accordingly, the connecting rib 128 c may form an angle and a position to correspond to the anti-rotation ring 191 inserted into the anti-rotation groove 154 of the orbiting scroll 150.

However, the anti-rotation pin 191 may not necessarily be installed to the connecting rib 128 c. In other words, when the anti-rotation pin 191 is coupled to the connecting rib 128 c, the position of the connecting rib 128 c may be constrained or limited to a position of the anti-rotation pin 191. Accordingly, instead of installing the anti-rotation pin 192 to the connecting rib 128 c, a fixed protrusion (not shown) may be provided at the storage space 124 between the connecting ribs 128 c, so as to increase design freedom for the connecting rib 128 c.

As described above, the oil storage space 124 may communicate with the oil separation space 123 via the oil return passage 127. Accordingly, an outlet end of the oil return passage 127 may be formed to communicate with any one of the plurality of oil storage chambers 124 a constituting the oil storage space 124.

The oil return passage 127 may be formed through a rear wall surface of the respective oil storage chamber. Alternatively, as illustrated in FIG. 10, an oil return protrusion (or return passage forming protrusion) 128 f provided therein with the oil return passage 127 may be formed. This allows rigidity of the rear housing 120 to be enhanced. The oil return protrusion 128 f may have a similar height to the height of the connecting rib 128 c.

Referring to FIGS. 9 and 10, a flow (or flow rate) controller 127 a may be installed at the oil return passage 127. The flow controller 127 a may control a flow rate of oil passing through the oil return passage 127, so that high-pressure oil, separated from the oil separation space 123, is reduced to an intermediate pressure when the oil is introduced into the oil storage space 124. Thus, the flow rate controller 127 a may be made of a pressure reducing member, such as a pressure reducing pin and a pressure reducing rod, having an outer diameter smaller than an inner diameter of the oil return passage 127.

Meanwhile, any one of the plurality of oil storage chambers 124 a may communicate with the oil guide passage 159 of the orbiting scroll 150. Accordingly, oil in the oil storage space 124 may flow into the rotating shaft coupling portion 153 via the oil guide passage 159. The oil may flow into the respective bearing surfaces and compression chambers through the oil supply passage 165 of the rotating shaft 160.

The oil storage space 124 according to this embodiment may have an annular shape. FIG. 11 is a planar view of an oil storage space according to another embodiment.

The oil storage space 124 according to the embodiment of FIG. 9 is divided into the plurality of oil storage chambers 124 a having an arc shape, whereas the oil storage space 124 according to the embodiment of FIG. 11 may have only one oil storage chamber 124 a. In this case, a volume of the storage space 124 may be further increased compared to the previous embodiment (the embodiment of FIG. 9) as the connecting ribs are excluded (or eliminated).

In addition, even in the case of this embodiment in which the oil storage space 124 is formed in an annular shape without being divided into a plurality oil storage chambers, the anti-rotation pin 192 may also be installed by forming a pin fixing protrusion 120 d provided at the oil storage space 124, as described above.

Referring back to FIGS. 6 and 7, the orbiting scroll 150 may include the orbiting end plate 151, the orbiting wrap 152, and the rotating shaft coupling portion 153.

The orbiting end plate 151 may be provided with a first guide passage 159 a formed at an edge thereof, and a second guide passage 159 b formed therein. The first guide passage 159 a defining an inlet end of the oil guide passage 159 may be recessed from the second side surface 151 b in an axial direction by a predetermined depth, and the second guide passage 159 b communicating with the first guide passage 159 a may be recessed to a predetermined depth in a radial direction. In addition, a third guide passage 159 c penetrating from the second guide passage 159 b to the first side surface 151 a of the orbiting end plate 151 may be formed at the central portion of the orbiting end plate 151. The third guide passage 159 c may penetrate through a rear wall surface of the rotating shaft coupling portion 153 to communicate with the rotating shaft coupling portion 153.

Further, the oil guide passage 159 may directly communicate with the suction chamber V1 or an intermediate pressure chamber V2, as well as the rotating shaft coupling portion 153. FIG. 12 is a cross-sectional view of an oil guide passage according to another embodiment.

Referring to FIG. 12, a fourth guide passage 159 d may be further provided at a middle portion of the oil guide passage 159, for example, penetrating from the second guide passage 159 b to an end portion of the orbiting wrap 152. The fourth guide passage 159 d may communicate with the end portion of the orbiting wrap 152 at a point or location where the fourth guide passage 159 d forms a suction pressure or an intermediate pressure. From this location, an oil supply communication groove 159 e may be further provided at the end portion of the orbiting wrap 152. The oil supply communication groove 159 e may be formed though a side wall surface of the orbiting wrap 152 so that oil flowing to the fourth guide passage 159 d is quickly introduced into the compression chamber V1 or the intermediate chamber V2.

Meanwhile, the thrust plate 180 described above may be installed between the orbiting scroll 150 and the rear housing 120. FIG. 13 is an enlarged cross-sectional view illustrating a portion of the motor-operated compressor according to an embodiment.

Referring to FIG. 13, the thrust plate 180 may be made of a material having higher wear resistance than the orbiting scroll 150 or the rear housing 120 since the thrust plate 180 is installed to reduce a friction loss and abrasion against the rear housing 120 while the orbiting scroll 150 performs an orbiting motion.

In addition, the thrust plate 180 may have an annular shape, and an outer circumferential surface thereof may be spaced apart from an inner circumferential surface of the compression unit accommodating space 121 of the rear housing 120 and an inner circumferential surface thereof may have the inner diameter equal to or larger than the inner diameter of the discharge space 122 so as to be located at the same position or outside of the discharge space 122. The thrust plate 180 may be provided with a plurality of pin holes 180 a to which the anti-rotation pin is coupled in a penetrating manner. The plurality of pin holes 180 a may be formed along a circumferential direction with a predetermined distance therebetween. The pin hole 180 a may be approximately equal to or slightly larger than the anti-rotation pin 192. Accordingly, the front-side intermediate pressure space S21 may communicate with the rear-side intermediate pressure space S22 via the pin hole 180 a.

In addition, the thrust plate 180 may be further provided with the oil communication hole 180 b that connects between the oil storage space 124 of the rear housing 120 and the oil guide passage 159 of the orbiting scroll 150. The oil communication hole 180 b may be provided at a position facing the oil guide passage 159 of the orbiting scroll 150. However, the oil communication passage 180 b may not necessarily be provided at the position facing the oil guide passage 159 if the front-side intermediate pressure space S21 and the rear-side intermediate pressure space S22 communicate with each other via the oil communication hole 159.

However, it may be preferable that the oil communication hole 180 b is disposed substantially at an opposite side of the oil return passage 127 based on the axial center Oc. For example, the outlet end of the oil return passage 127 may be provided at the lowest point of the oil storage space 124 as possible, so that oil separated in the oil separation space 123 is quickly introduced into the oil storage space 124. Accordingly, the oil communication hole 180 b may be provided at the highest point or near the highest point of the oil storage space 124. This allows oil introduced into the oil storage space 124 to almost fill the entire oil storage space 124. Then, the oil flows into the oil communication hole 180 b, so as to make all of the plurality of anti-rotation pins 192 contact with the oil in the oil storage space 124, thereby effectively lubricating between the anti-rotation pin 192 and the anti-rotation ring 191.

In the drawings, unexplained reference numerals 135 and V3 denote a winding coil and a discharge chamber, respectively.

The motor-operated compressor according to the embodiments may operate as follows.

When power is applied to the drive motor 130, the rotating shaft 165 may transfer a rotational force to the orbiting scroll 150 while rotating together with the rotor 132. This allows the orbiting scroll 150 with a pin-and-ring structure to perform an orbiting motion. Accordingly, the compression chamber V is reduced in volume while continuously moving toward a central part or side.

Then, a refrigerant flows into the suction space S1, which is the motor chamber, through the inlet port 111, and passes through a flow path provided between an outer circumferential surface of the stator 131 and the inner circumferential surface of the main housing 110, an air gap between the stator 131 and the rotor 132, or a gap between a stator core (not shown) and the winding coil 135, and is then introduced into the compression chamber V via the suction port 145.

Then, the refrigerant is compressed by the fixed scroll 140 and the orbiting scroll 150 while the orbiting scroll 150 orbits (or rotates) with respect to the fixed scroll 140. The compressed refrigerant is discharged into the discharge space 122 provided at the rear housing 120 via the discharge port 157. This refrigerant is then introduced into the oil separation space 123 from the discharge space 122 via the oil separation communication hole 122 a, so as to separate oil from the refrigerant. After separation, the refrigerant is discharged to a refrigeration cycle through the exhaust port 126, whereas the oil in a mist state flows into the oil storage space 124 through the oil return passage 127. As the oil return passage 127 is provided with the flow controller 127 a made of a pressure reducing member, the oil in a high-pressure state is depressurized or reduced to an intermediate pressure, and is then introduced into the oil storage space 124.

Then, an amount of the oil introduced into the oil storage space 124 is gradually increased to a predetermined oil level. The oil storage space 124 is divided into the plurality of oil storage chambers 124 a by the connecting ribs 128 c, and the oil return passage 127 communicates with an oil storage chamber located at the lowest position of the oil storage chambers 124 a. However, as the height of the connecting rib 128 c is lower than the height of the second scroll support surface 125, or the oil storage chamber connecting passage 128 d is provided at the connecting rib 128 c, the oil introduced into the storage chamber located at the lowest position flows into another oil storage chamber, thereby increasing the oil level.

Then, oil is filled in the rear-side intermediate pressure space S22, and this oil flows into the front-side intermediate pressure space S21 through the oil communication hole 180 b provided at the thrust plate 180. The oil filled in the rear-side intermediate pressure space S22 fills the front-side intermediate pressure space S21 sealed between the scroll-side first sealing member 181 and the scroll-side second sealing member 182. When oil is filled to a predetermined oil level of the front-side intermediate pressure space S21, the oil flows to the rotating shaft coupling portion 153 via the oil supply passage 159 provided at the orbiting scroll 150. As oil is filled in the front-side intermediate pressure space S21, the oil is smeared on each of the anti-rotation pins 192 penetrating through the thrust plate 180 to be accommodated in the front-side intermediate pressure space S21, thereby lubricating between the anti-rotation pin 192 and the anti-rotation ring 191.

Meanwhile, oil introduced into the rotating shaft coupling portion 153 is supplied to the bearing surface between the main bearing portion 162 of the rotating shaft 165 and the main bearing 171, and the bearing surface between the eccentric portion 164 of the rotating shaft 165 and the eccentric bearing 173 via the oil supply groove 165 a provided at the rear end of the rotating shaft 165 and the oil supply holes 165 b and 165 c, thereby lubricating the respective bearing surfaces. The oil lubricating the respective bearing surfaces lubricates a lubricated surface between the fixed scroll 140 and the orbiting scroll 150 through a gap of the bearing surfaces, and is then introduced into the compression chamber V to be discharged together with a refrigerant. Such series of processes are repeated.

Here, as the fourth guide hole 159 d formed through the orbiting wrap 152 at a middle portion of the guide passage 159 is provided at the orbiting scroll 150 toward the suction chamber V1, some or part of oil flowing into the rotating shaft coupling portion 153 flows into the suction chamber V1 through the oil guide passage 159, thereby evenly lubricating between the fixed scroll 140 and the orbiting scroll 150.

Although not illustrated in the drawings, instead of separately providing the oil separation space described above, an inlet end of the oil return passage may communicate with the discharge space. Here, an oil separation portion (e.g., a collision-type oil separation portion or separator) may be separately provided in the discharge space, so that oil separated from the oil separation portion may be returned to the oil storage space via the oil return passage.

In a motor-operated compressor according to embodiments, a horizontal and frame scroll type motor-operated compressor is employed to exclude or remove a frame. This allows the number of components and manufacturing costs to be reduced, thereby achieving the smaller and lighter weight motor-operated compressor.

In addition, a sufficient oil storage space for oil separated from a refrigerant in a compression chamber can be ensured by providing the oil storage space at the adjacent to a discharge space of a rear housing. This allows stored oil to be quickly supplied to an area requiring lubrication. Accordingly, friction loss or abrasion caused by an insufficient amount of oil can be reduced, thereby improving compressor efficiency.

Further, the rear housing may be easily fabricated by providing the oil storage space at one side surface of the rear housing in an opened manner. Accordingly, manufacturing costs of the rear housing can be reduced and a sufficient oil storage space can be secured. 

What is claimed is:
 1. A motor-operated compressor, comprising: a main housing having a suction space; a motor unit disposed in the suction space; a rotating shaft coupled to the motor unit; a fixed scroll coupled to the main housing, the fixed scroll being configured to support the rotating shaft, and including an inlet port communicating with the suction space; an orbiting scroll coupled to the rotating shaft and configured to perform an orbiting motion with respect to the fixed scroll, the orbiting scroll forming a compression space with the fixed scroll, and including a discharge port; and a rear housing coupled to the main housing, wherein the rear housing includes a discharge space configured to communicate with the discharge port of the orbiting scroll, the discharge space is disposed adjacent to a central portion of a surface facing the orbiting scroll, an oil storage space disposed adjacent to an edge portion of the surface facing the orbiting scroll, and an oil return passage configured to guide oil separated in the discharge space to the oil storage space.
 2. The motor-operated compressor of claim 1, wherein the oil storage space includes an annular recess extending from a surface facing the orbiting scroll into the rear housing.
 3. The motor-operated compressor of claim 2, wherein the rear housing includes a first annular-shaped support surface formed at an inner circumferential side of the oil storage space, first annular-shaped support surface separating the oil storage space and the discharge space, the first annular-shaped support surface includes a first sealing member configured to provide a seal between the oil storage space and the discharge space, the rear housing includes a second annular-shaped support surface formed at an outer circumferential side of the oil storage space, and the second annular-shaped support surface includes a second sealing member configured to provide a seal between the oil storage space and the suction space.
 4. The motor-operated compressor of claim 3, further including at least one oil storage space partitioning protrusion extending between the first annular-shaped support surface and the second annular-shaped support surface, wherein the oil storage space partitioning protrusion has an axial height lower than axial heights of the first annular-shaped support surface and the second annular-shaped support surface.
 5. The motor-operated compressor of claim 3, further including at least one oil storage space partitioning protrusion extending between the first annular-shaped support surface and the second annular-shaped support surface, the at least one oil storage space partitioning protrusion configured to separate the oil storage space into adjacent oil storage spaces, wherein the oil storage space partitioning protrusion includes a space communication groove configured to communicate the adjacent oil storage spaces.
 6. The motor-operated compressor of claim 3, further including at least one oil storage space partitioning protrusion extending between the first annular-shaped support surface and the second annular-shaped support surface, wherein the oil storage space partitioning protrusion includes an anti-rotation pin rotatably inserted into an anti-rotation ring provided in the orbiting scroll.
 7. The motor-operated compressor of claim 3, wherein the oil storage space includes a plurality of pin fixing protrusions circumferentially spaced apart from each other by a predetermined distance, and each of the plurality of pin fixing protrusions includes an anti-rotation pin rotatably inserted into an anti-rotation ring provided in the orbiting scroll.
 8. The motor-operated compressor of claim 1, wherein an outlet end of the oil return passage communicates with the oil storage space at a position lower than a position of the discharge space, and the oil return passage includes a flow controller configured to control a flow rate of oil passing through the oil return passage.
 9. The motor-operated compressor of claim 1, wherein the orbiting scroll includes an oil guide passage, wherein one end of the oil guide passage communicates with the oil storage space of the rear housing.
 10. The motor-operated compressor of claim 9, wherein a central portion of the orbiting scroll includes a rotating shaft coupling portion, the rotating shaft is inserted into and coupled to the rotating shaft coupling portion, and the oil guide passage communicates with the rotating shaft coupling portion.
 11. The motor-operated compressor of claim 10, wherein an end portion of the rotating shaft is inserted into the rotating shaft coupling portion and includes an oil supply passage that communicates with the oil guide passage, and the oil supply passage includes an oil supply groove extending into the end portion of the rotating shaft in an axial direction, and a plurality of oil supply holes extending from the oil supply groove toward the rotating shaft coupling portion.
 12. The motor-operated compressor of claim 11, wherein the oil guide passage is positioned higher than the oil return passage, the orbiting scroll includes a low-pressure side oil supply passage communicating with the oil guide passage, and the low-pressure side oil supply passage includes a low-pressure side oil supply hole axially penetrating through an orbiting wrap of the orbiting scroll.
 13. The motor-operated compressor of claim 12, wherein an end portion of the orbiting wrap facing the fixed scroll includes an oil supply communication groove, and the oil supply communication groove is configured to be connected to a side wall surface of the orbiting wrap.
 14. The motor-operated compressor of claim 1, further including a thrust plate positioned between the orbiting scroll and the rear housing, a plurality of scroll-side sealing members provided between the thrust plate and the orbiting scroll, the scroll-side sealing members radially spaced apart at predetermined intervals, and a plurality of housing-side sealing members provided between the thrust plate and the rear housing, the oil storage space being interposed between the housing-side sealing members.
 15. The motor-operated compressor of claim 14, wherein the thrust plate includes a plurality of pin holes formed along a circumferential direction, each of the pin holes being configured to receive an anti-rotation pin, and at least one communication hole configured to provide communication between the plurality of scroll-side sealing members and the plurality of housing-side sealing members.
 16. A motor-operated compressor, comprising: a first housing having a suction space; a motor unit positioned at one end of the first housing; a rotating shaft coupled to the motor unit; a first scroll disposed in the suction space of the first housing and positioned at an opposite end of the first housing facing the motor unit, the first scroll being coupled to the first housing and configured to support the rotating shaft, the first scroll including an inlet port communicating with the suction space; a second scroll coupled to the rotating shaft and configured to perform an orbiting motion with respect to the first scroll, the second scroll forming a compression space at a first side surface thereof facing the first scroll, and including a discharge port; and a second housing positioned facing a second side surface opposite to the first side surface of the second scroll, the second housing being coupled to the first housing, wherein the second housing includes a discharge space communicating with the discharge port of the second scroll, the discharge space being formed adjacent to a central portion of a surface of the second housing facing the second scroll, an oil separation space positioned on one side of the discharge space, the oil separation space configured to communicate with the discharge space, and an oil storage space formed adjacent to an edge portion of the surface of the second housing facing the second scroll, the oil storage space being configured to communicate with the oil separation space.
 17. The motor-operated compressor of claim 16, wherein the second scroll includes an oil guide passage configured to communicate with the oil storage space of the second housing, and the rotating shaft includes an oil supply passage configured to communicate with the oil guide passage.
 18. A motor-operated compressor, comprising: a main housing extending from a closed end to an open end; a fixed scroll positioned between the closed end and the open end and coupled to the main housing, the fixed scroll and the closed end defining a suction space, the fixed scroll including an inlet port connected to the suction space and a central bore; a motor unit disposed in the suction space; an orbiting scroll positioned between the fixed scroll and the open end, the orbiting scroll forming a compression space with the fixed scroll, and including a discharge port; a rotating shaft coupled to the motor unit, the rotating shaft extending through the central bore and being coupled to the orbiting scroll; a bearing disposed in the central bore of the fixed scroll and configured to support the rotating shaft; and a rear housing attached to the open end of the main housing, the rear housing including: a discharge space disposed adjacent a radially central portion of the rear housing and configured to communicate with the discharge port of the orbiting scroll; an oil storage space arranged to circumscribe the discharge space; and an oil return passage connecting the discharge space and the oil storage space.
 19. The motor-operated compressor of claim 18, further including a bearing disposed at the closed end of the main housing and configured to support the rotating shaft.
 20. The motor-operated compressor of claim 18, wherein the rotating shaft includes an eccentric portion including a center spaced apart from a center of the rotating shaft, and the eccentric portion is coupled to the orbiting scroll. 